Hello Ankit,
Thank you for your reply. I appreciate taking the time to write back.
Disabling and enabling all the plugins seems to have solved the problem for me (thank goodness, I was having trouble restoring a backup)
Anyway, thank you for your help, I can’t believe I missed such an obvious troubleshooting step this time around. I will adjust my rating based on your support here, but I cannot give 5 stars yet, since two separate cart problems have occured after installing this plugin on two different wordpress versions and the problem didn’t reoccur after enabling all the other plugins one by one. (I can email you a list of the plugins I have installed if you want to take a look)
I don’t know which of my plugins would cause a conflict, since only my third-party checkout plugin is directly involved with the cart, but at a later step. I can’t say I’m familiar with all of the code, though.